This invention relates to a device for mounting an upper structure such as a cab on a frame of, for example, an earth-moving or construction vehicle. More specifically, the invention relates to a device for elastically supporting the upper structure on the frame and thus reducing the vibration transmitted from the frame to the upper structure.
In an earth-moving vehicle such as a tractor, the cab is mounted on the frame. The frame vibrates during vehicle operation, and when the vibration is directly transmitted to the cab, the operator in the cab is subjected to this vibration. Since the earth-moving vehicle is generally operated continuously for long periods of time, the above vibration becomes an important problem.
With a view towards reducing this vibration, a mounting device was proposed in which an elastic member is interposed between the frame and the cab of a vehicle to support the cab elastically on the frame by the compression elasticity of the elastic member, to thereby reduce the vibration transmitted from the frame to the cab. Such a mounting device is disclosed, for example, in Japanese Utility Model application No. 75525/71 (laid open to public inspection under Japanese Laid-Open Utility Model Publication No. 33019/73).
Such a mounting device is still not fully satisfactory. In this mounting device, an elastic member having a relatively high coefficient of elasticity must be used to support the cab on the frame stably, and therefore, the vibration transmitted from the frame to the cab cannot be fully reduced. In addition, with the conventional mounting device, the cab cannot be firmly supported in a horizontal direction. When a high rate of acceleration is exerted on the vehicle, the conventional mounting device cannot support the cab with high reliability. Another disadvantage of the conventional mounting device is that mounting of the cab on the frame is relatively difficult and the elastic properties of the elastic member varies according to the tightening torque at the time of assembling, whereby the elastic member may deteriorate within a relatively short period of time.
Accordingly, a main object of this invention is to provide an improved mounting device capable of supporting an upper structure such as a cab on a frame both in the vertical and horizontal directions with high reliability, and sufficiently reducing the vibration transmitted from the frame to the upper structure.
Another object of this invention is to provide such a mounting device with which the cab can be mounted relatively simply.
Still another object of this invention is to provide such a mounting device having a relatively long effective life.
A further object of this invention is to provide an earth-moving or construction vehicle in which a cab is mounted on a frame by such a mounting device.